|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
namespace Lesson09; |
|
4
|
|
|
|
|
5
|
|
|
class CountSemiprimes |
|
6
|
|
|
{ |
|
7
|
|
|
public function solution($N, $P, $Q) |
|
8
|
|
|
{ |
|
9
|
|
|
$initialArrayCount = count($P); |
|
10
|
|
|
$primes = array_values($this->filterPrimes($N, $this->getPrimes($N))); |
|
11
|
|
|
$primeCount = count($primes); |
|
12
|
|
|
$semiPrimes = $this->getSemiPrimes($N, $primeCount, $primes); |
|
13
|
|
|
ksort($semiPrimes); |
|
14
|
|
|
|
|
15
|
|
|
$assignableValue = 1; |
|
16
|
|
|
foreach ($semiPrimes as $value) { |
|
17
|
|
|
$semiPrimes[$value] = $assignableValue; |
|
18
|
|
|
$assignableValue++; |
|
19
|
|
|
} |
|
20
|
|
|
|
|
21
|
|
|
$semiPrimesInRange = []; |
|
22
|
|
|
|
|
23
|
|
|
for ($i = 0; $i < $initialArrayCount; $i++) { |
|
24
|
|
|
$pValue = $P[$i]; |
|
25
|
|
|
$qValue = $Q[$i]; |
|
26
|
|
|
$range = $qValue - $pValue; |
|
27
|
|
|
|
|
28
|
|
|
$leftKey = $this->getKey($pValue, $semiPrimes, $range); |
|
29
|
|
|
$rightKey = $this->getKey($qValue, $semiPrimes, $range); |
|
30
|
|
|
|
|
31
|
|
|
if ($leftKey === null || $rightKey === null) { |
|
32
|
|
|
$semiPrimesInRange[] = 0; |
|
33
|
|
|
} elseif ($rightKey === $leftKey) { |
|
34
|
|
|
$semiPrimesInRange[] = 1; |
|
35
|
|
|
} else { |
|
36
|
|
|
$semiPrimesInRange[$i] = $semiPrimes[$rightKey] - $semiPrimes[$leftKey] + 1; |
|
37
|
|
|
} |
|
38
|
|
|
} |
|
39
|
|
|
|
|
40
|
|
|
return $semiPrimesInRange; |
|
41
|
|
|
} |
|
42
|
|
|
|
|
43
|
|
|
/** |
|
44
|
|
|
* @param $N |
|
45
|
|
|
* |
|
46
|
|
|
* @return array |
|
47
|
|
|
*/ |
|
48
|
|
|
private function getPrimes($N) |
|
49
|
|
|
{ |
|
50
|
|
|
$primes = []; |
|
51
|
|
|
for ($i = 2; $i <= $N; $i++) { |
|
52
|
|
|
$primes[$i] = $i; |
|
53
|
|
|
} |
|
54
|
|
|
|
|
55
|
|
|
return $primes; |
|
56
|
|
|
} |
|
57
|
|
|
|
|
58
|
|
|
/** |
|
59
|
|
|
* @param $N |
|
60
|
|
|
* @param $primes |
|
61
|
|
|
* |
|
62
|
|
|
* @return int |
|
63
|
|
|
*/ |
|
64
|
|
|
private function filterPrimes($N, $primes) |
|
65
|
|
|
{ |
|
66
|
|
|
$initialValue = 2; |
|
67
|
|
|
while ($initialValue * $initialValue <= $N) { |
|
68
|
|
|
for ($j = $initialValue + $initialValue; $j <= $N; $j += $initialValue) { |
|
69
|
|
|
unset($primes[$j]); |
|
70
|
|
|
} |
|
71
|
|
|
$initialValue++; |
|
72
|
|
|
} |
|
73
|
|
|
|
|
74
|
|
|
return $primes; |
|
75
|
|
|
} |
|
76
|
|
|
|
|
77
|
|
|
/** |
|
78
|
|
|
* @param $N |
|
79
|
|
|
* @param $primeCount |
|
80
|
|
|
* @param $primes |
|
81
|
|
|
* |
|
82
|
|
|
* @return array |
|
83
|
|
|
* |
|
84
|
|
|
* @internal param $semiPrimes |
|
85
|
|
|
*/ |
|
86
|
|
|
private function getSemiPrimes($N, $primeCount, $primes) |
|
87
|
|
|
{ |
|
88
|
|
|
$semiPrimes = []; |
|
89
|
|
|
for ($i = 0; $i < $primeCount; $i++) { |
|
90
|
|
|
for ($j = $i; $j < $primeCount; $j++) { |
|
91
|
|
|
$primesProduct = $primes[$i] * $primes[$j]; |
|
92
|
|
|
if ($primesProduct <= $N) { |
|
93
|
|
|
$semiPrimes[$primesProduct] = $primesProduct; |
|
94
|
|
|
} else { |
|
95
|
|
|
break; |
|
96
|
|
|
} |
|
97
|
|
|
} |
|
98
|
|
|
} |
|
99
|
|
|
|
|
100
|
|
|
return $semiPrimes; |
|
101
|
|
|
} |
|
102
|
|
|
|
|
103
|
|
|
/** |
|
104
|
|
|
* @param $value |
|
105
|
|
|
* @param $semiPrimes |
|
106
|
|
|
* @param $range |
|
107
|
|
|
* |
|
108
|
|
|
* @return key |
|
109
|
|
|
*/ |
|
110
|
|
|
private function getKey($value, $semiPrimes, $range) |
|
111
|
|
|
{ |
|
112
|
|
|
$key = null; |
|
113
|
|
|
if (array_key_exists($value, $semiPrimes)) { |
|
114
|
|
|
$key = $value; |
|
115
|
|
|
} else { |
|
116
|
|
|
for ($j = 1; $j <= $range; $j++) { |
|
117
|
|
|
if (array_key_exists($value + $j, $semiPrimes)) { |
|
118
|
|
|
$key = $value + $j; |
|
119
|
|
|
break; |
|
120
|
|
|
} |
|
121
|
|
|
} |
|
122
|
|
|
} |
|
123
|
|
|
|
|
124
|
|
|
return $key; |
|
125
|
|
|
} |
|
126
|
|
|
} |
|
127
|
|
|
|
samiulhoque /
codility-lessons
